I think, that of gay marriage is legal, nobody should be able to turn it away, by law. But it will be boiled down to personal belief, and disrespect to god or something of the sort, and that's where the complications will arise, as they always do. If I lived in a country where it was legal, I wouldn't want to have to search for a specific church. Because if it was an actual right, we wouldn't have to fight for it and comply to religious notions like finding separate churches to marry in.
“Whoever will be free must make himself free. Freedom is no fairy gift to fall into a man's lap. What is freedom? To have the will to be responsible for one's self.” - Max Stirner.